The end of
January marks a somber time for NASA with the anniversary of the three major
tragedies in the history of U.S. spaceflight.

On Jan. 27,
1967, three of the first group of NASA astronauts - Virgil ?Gus? Grissom,
Edward White and Roger Chaffee - died during a routine
ground test of the Apollo capsule, later named Apollo 1.

The
astronauts suffocated when an electrical spark ignited a fire that engulfed
their high-pressurized, pure-oxygen cabin. The Apollo 1 ground test had not
been designated as potentially hazardous, the NASA History Web site said.

These were
the first U.S. astronaut deaths associated with spaceflight. Sadly, that
accident was not the last such tragedy.

The highly
anticipated Jan. 28, 1986, launch of Space
Shuttle Challenger, which carried the first teacher-astronaut, Christa
McAuliffe, was watched live by many around the nation, including school
children. But 73 seconds after takeoff, the shuttle erupted in a fireball that killed
the entire crew.

In June
1986, the Presidential Commission on the Space Shuttle Challenger Accident,
chaired by William P. Rogers, found that the O-ring seals in the right
solid-rocket booster failed in the cold temperature, eventually causing the
booster to rupture and explode, taking the lives of McAuliffe and astronauts
Francis ?Dick? Scobee, Ron McNair, Mike Smith, Ellison Onizuka, Judy Resnik and
Greg Jarvis. A complete failure of the O-ring was not expected at frigid
temperatures, said Roger Launius, chairman of the Washington-based space
history division of the Smithsonian Institute.

A gouge in
the shuttle?s left wing absorbed too much heat as the shuttle re-entered
Earth?s atmosphere. NASA officials did not believe that the gouge on the wing -
caused by the impact of insulating foam from the shuttle?s external tank during
its Jan. 16 liftoff - was severe enough to cause the loss of the shuttle,
Launius said.

?The
problem with all three of these accidents is they really didn?t know they had a
problem,? Launius said in a phone interview.

However,
certain individuals did in fact raise awareness about these and other issues.
Roger Boisjoly, an engineer for Morton Thiokol which built the space shuttle
rocket boosters, warned his superiors and NASA officials that the O-rings might
not hold up in cold temperatures. While there had been problems with the O-ring
seals during previous shuttle flights, there never was a total breach, Launius
said. And without the necessary amount of hard evidence, those objections were
not seen as sufficient enough to stop a shuttle launch, he said.

There was
not a thorough enough understanding of these risks, he said.

The
inability to communicate potential problems in an understandable way between
the different groups working on the spacecraft contributed to the accidents
that led to the astronauts? deaths, Launius said.

After all
three accidents, new protocols immediately were implemented to prevent the
problems in the future, including:

The hatch
for the Apollo capsule was reworked to allow faster egress, wiring was
redone, flammable materials inside the cabin were replaced with
flame-retardant items and the cabin pressure was lessened.

The
O-rings for the shuttle?s solid-rocket boosters were redesigned after the
Challenger disaster.

Foam
debris hitting the shuttle was strictly scrutinized after the loss of Columbia, according to the NASA History Web site.

Despite the
risks, astronauts continue to risk their lives. ?The spirit of exploration is
truly what it is to be human,? astronaut Stephen Robinson said in an August
2005 audio message on flight STS-114,
which directly followed the Columbia disaster.

?[W]e hope
if anything happens to us, it will not delay the program,? Grissom said just a
few weeks before he died, the NASA History Web site said. ?The conquest of
space is worth the risk of life.?